That part of a work of one author found in another is not of itself piracy, or sufficient to support an action; a man may adopt part of the work of another; he may so make use of another’s labors for the promotion of science and the benefit of the public. – Lord Ellenborough, quoted in Bouvier’s Law Dictionary by John Bouvier, 8th

Whenever we would prepare the mind by a forcible appeal, an opening quotation is a symphony preluding on the chords whose tones we are about to harmonize. – Isaac D’Israeli, “Quotation,” A Second Series of Curiosities of Literature

Miss Amesbury is especially happy in the use of quotations—and an apt quotation is like a lamp which flings its light over the whole sentence. – L.E. Landon, Romance and Reality, 1832